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PropertyNotFoundException in form

kaech

I am trying to map JavaBean properties to form properties as described in the user guide.

<userTask id="order" name="order" activiti:formKey="order.form">
<documentation>order</documentation>
<extensionElements>
<activiti:formProperty id="quantity" variable="quantity" expression="#{order.quantity}" required="true" type="long" />
</extensionElements>
…
</userTask>

In the form I always get a javax.el.PropertyNotFoundExeption for the property quantity.
In ACT_RU_VARIABLE I only see the serialized JavaBean.
${order.quantity} is available in the form but ${quantity} is not.

Do you have any advice?

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Comments

frederikherema1

Hi,

The "variable" attribute means that the value should be fetched from variable ${quantity}. You should just remove the variable attribute, if you're using the expression.

kaech

I tried it, but it does not work.

This is what I did:
<activiti:formProperty id="quantity" expression="#{order.quantity}" required="true" type="long" />

Do you have any other suggestions?

frederikherema1

Does your order-bean actually have a getQuantity()? The ELResolver resolves part by part, so when he's complaining about 'quantity' it might as well be the '.quantity' in 'order.quantity'…

kaech

I double checked, getQuantity is there.
I renamed quantity to thequantity like this:

<activiti:formProperty id="thequantity" expression="#{order.quantity}" required="true" type="long" />

Now Activiti throws a PropertyNotFoundException for thequantity.
In the form ${order.quantity} works but not ${thequantity}.

frederikherema1

Thats really strange… Could you perhaps create a test-case for this (http://activiti.org/userguide/index.html#apiUnitTesting), because I checked the code that is responsible for getting/setting form-property values, and error shouldn't occur when expression is filled in.

kaech

Yes, but that might take a while.
I am using Activiti 5.2. Could that be the reason?

frederikherema1

Hi,

Thats a possibility, although I don't see any changes to that are on first sight in SVN history…

kaech

Do I have to declare the taks form properties before they can be used?

The userguide says:
"So there is no need to declare task form properties if they match 1-1 with the process variables."

But what if they don't match 1-1 as in my case?

I never declared the task form properties and they are not submitted during the startEvent.
Could that be the problem?

frederikherema1

Not really sure shat you mean.

"So there is no need to declare task form properties if they match 1-1 with the process variables."

If you submit form-property values (in the Map<String, String>) for which no formProperty is defined in the process-definition, the form property value is just submitted (string) variable with the name of the variable equal to the id of the property (key in the map).

kaech

I mean that I don't declare the task form properties anywhere. The only occurences are shown below in red.
The process is started using the Activiti Explorer. So thequantity is not provided by the caller when the process starts.

order.bpmn2.0.xml
<?xml version="1.0" encoding="UTF-8"?>
<definitions xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL"
   xmlns:activiti="http://activiti.org/bpmn"
   xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI"
   xmlns

mgdc="http://www.omg.org/spec/DD/20100524/DC"
xmlns

mgdi="http://www.omg.org/spec/DD/20100524/DI"
   xmlns:signavio="http://www.signavio.com"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   expressionLanguage="http://www.w3.org/1999/XPath"
   id="sid-95da716d-f515-46b8-8677-56a60dbc13c5"
   targetNamespace="http://www.signavio.com/bpmn20"
   typeLanguage="http://www.w3.org/2001/XMLSchema"
   xsi:schemaLocation="http://www.omg.org/spec/BPMN/20100524/MODEL http://www.omg.org/spec/BPMN/2.0/20100501/BPMN20.xsd">

   <process id="order" isClosed="false" isExecutable="true" name="order" processType="None">

      <startEvent id="start" name="Start"/>

      <sequenceFlow id="flow4" sourceRef="start" targetRef="init"/>

      <scriptTask id="init" name="Init" scriptFormat="groovy">
         <script>
         order = new org.example.Order(quantity:2)
         </script>
      </scriptTask>

      <sequenceFlow id="flow3" sourceRef="init" targetRef="placeorder"/>

      <userTask id="placeorder" name="Place order" activiti:formKey="order.form">
         <documentation>order</documentation>
         <extensionElements>
             <activiti:formProperty id="thequantity" expression="#{order.quantity}" />
         </extensionElements>
         <potentialOwner>…</potentialOwner>
      </userTask>

      <sequenceFlow id="flow2" sourceRef="placeorder" targetRef="orderfood"/>

      <scriptTask id="orderfood" name="Order food" scriptFormat="groovy">
         <script>out

rint "Ordering $order.quantity\n"</script>
      </scriptTask>

      <sequenceFlow id="flow1" sourceRef="orderfood" targetRef="end"/>

      <endEvent id="end" name="End"/>

   </process>

</definitions>

order.form
<h1>order</h1>
Quantity is ${thequantity}

Is this really enough to map process variables to task form properties?

frederikherema1

I see what you are trying to do here… You're mixing up the built-in rendering (that only resolves variables in the HTML expressions, in your order.form) with the form-properties. Form properties should be used when you want to render your own forms, not using getRendered(Start)Form. So the error resulted from rendering the form, rather than getting the form-properties.

Basically, you should decide wether you want to use built-in form rendering (eg. html-forms used in explorer) or use form-properties which you declare with the activiti:formProperty.

Check out http://activiti.org/userguide/index.html#forms -> Built in vs. form properties

kaech

Ah, I see. Thanks.

I am trying to implement an external UI so using form-properties is basically the right approach.
Since my client is external to the Activiti/Tomcat deployment I wanted to use the REST interface (activiti-rest).

When I try that I am getting the same exception:

PropertyNotFoundException: Cannot find property thequantity

Aren't the form-properties exposed via the REST-API?

frederikherema1

In the 5.4 release, they are

You shouldn't use the *.form files (and formKey) if you want external rendering

kaech

That's good news. I'll wait for the 5.4. release then.
By the way, are there any plans to expose the serialized JavaBeans via the REST interface as well?
For external UI-Clients it would be great not to be limited to to the flat form-property representation but also having access to the complex process data.

frederikherema1

Nothing planned in that direction… but the form-type mechanism is pluggable. So you could easily write a FormType that handles conversion of serializable -> String and visa versa.

see org.activiti.engine.impl.form.AbstractFormType, ProcessEngineConfigurationImpl.customFormTypes

kaech

Is it possible to plug-in a custom form type via configuration?
Or do I have to change the Activiti sourcecode?

frederikherema1

It can be done using configuration, ProcessEngineConfigurationImpl.customFormTypes:

<br><bean id="processEngineConfiguration" class="org.activiti.engine.impl.cfg.StandaloneProcessEngineConfiguration"><br>&nbsp;&nbsp;&nbsp; &hellip;<br>&nbsp;&nbsp;&nbsp; <property name="customFormTypes"><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <list><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <ref bean="myFormType"/><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </list><br>&nbsp;&nbsp;&nbsp; </property><br>&nbsp;&nbsp;&nbsp; &hellip;<br>

kaech

I implemented a custom form type derived from AbstractFormType and declared it in activiti.cfg.xml of the activiti-rest application as you described in your previous post.

The method getName returns order as the name.

In the process definition I added

<activiti:formProperty id="theorder" expression="#{order}" type="order"/>

to expose the whole order class as a form property.
When I upload the process I get the message unknown type 'order' ….

How do I have to define the formProperty in order to let Actitivi use my custom form type class?

frederikherema1

Adding your type to the custom from-types should do the trick:

<br>protected void initFormTypes() {<br>&nbsp;&nbsp;&nbsp; if (formTypes==null) {<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; formTypes = new FormTypes();<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; formTypes.addFormType(new StringFormType());<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; formTypes.addFormType(new LongFormType());<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; formTypes.addFormType(new DateFormType("dd/MM/yyyy"));<br>&nbsp;&nbsp;&nbsp; }<br>&nbsp;&nbsp;&nbsp; if (customFormTypes!=null) {<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; for (AbstractFormType customFormType: customFormTypes) {<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; formTypes.addFormType(customFormType);<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; }<br>&nbsp;&nbsp;&nbsp; }<br>&nbsp; }<br>

Do you get the error when deploying? or when running the process?

kaech

Is it really necessary to change the source code?
I added the new form type to activiti.cfg.xml as you descibed earlier, but it doesn't seem to work.
I changed the configuration in ..\webapps\activiti-rest\web-inf\lib\activiti-cfg.jar
Is this the right place?

The error is raised during deployment.

frederikherema1

No, it's not necessary to change source-code, just showed an extract of how the form-property types are determined in the engine.

Can you paste your config file?

kaech

Here you go.

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans   http://www.springframework.org/schema/beans/spring-beans.xsd">

<bean id="orderFormType" class="org.example.OrderFormType"/>

<bean id="processEngineConfiguration" class="org.activiti.engine.impl.cfg.StandaloneProcessEngineConfiguration">

    <property name="jobExecutorActivate" value="true" />
    <property name="history" value="audit" />

    <property name="customFormTypes">
       <list>
         <ref bean="orderFormType"/>
       </list>
    </property>

    <!– Database configurations –>
    <property name="databaseSchemaUpdate" value="true" />
    <property name="jdbcUrl" value="jdbc:h2:tcp://localhost/activiti" />
    <property name="jdbcDriver" value="org.h2.Driver" />
    <property name="jdbcUsername" value="sa" />
    <property name="jdbcPassword" value="" />

    <property name="jobExecutorActivate" value="true" />

    <property name="dbCycleUsed" value="true" />

</bean>

</beans>

kaech

I still can't get it to work.
Any news on that?

frederikherema1

How do you load your process-engine? The configuration-file you pasted above can never work, since it contains duplicate 'jobexecutor' property:

<br>Configuration problem: Multiple 'property' definitions for property 'jobExecutorActivate'<br>Offending resource: resource loaded through InputStream<br>Bean 'processEngineConfiguration'<br>

So I guess the engine you are using isn't the one you think it is

kaech

Oh, I overlooked the jobexecutor setting.
I am using the engine integrated in the Tomcat installation and deploy the process via the Explorer. I updated the activiti.cgf.xml in the activiti-rest application inside the Tomcat webapps directory.

Which config file do I have to update to apply the config changes?

frederikherema1

The activiti.cfg.xml in the activiti.cfg.jar in webapps/activiti-rest/WEB-INF/lib/. In activiti probe, you can see which engine is used (on start page), this includes the resource it was initialized from. Check this, should be the one in aciviti.cfg.lib$activiti.cfg.xml

kaech

The configuration issue is solved now. Thank you.

In the meantime I installed Activiti 5.4. cause it is supposed to expose form properties via activiti-rest.
Unfortunately the original problem is still there.

This is what I did:

I am exposing the following form property in a userTask:

<activiti:formProperty id="thequantity" expression"#{order.form}"/>

When calling http://.../activiti-rest/service/task/<taskid>/form

I am getting PropertyNotFoundException: Cannot find property thequantity

Actually the whole scenario is very simple.
Do you have an idea what could be wrong here?

kaech

In the 5.4 release, they are You shouldn't use the *.form files (and formKey) if you want external rendering

Does that mean I need to remove the formKey attribute to make it work?

kaech

I tried to remove the formkey attribute from the user task.
Now I get a WebScriptException: There is no form for task …
Of course, that is what I expected.

To summarize what I am trying to do:

1. Connect a client which has no access to the Activiti API.
2. Connect the client via activiti-rest.
3. Use an existing JavaBean as process model.
4. Serialize the Java Bean using a custom form type class.
4. Expose parts of the JavaBean as form properties to get access in the client.

After all my investigation it seems that <activiti:formProperty …> is not yet properly supported in Activiti. Currently there seems to be no way to combine external clients in case the form properies differ from the process properties.

I think in non trivial enterprise environments it is very important to be able to modify complex (JavaBeans based) process models using arbitrary clients via REST.

Is there a roadmap for that?
If not, what is you suggestion for those kinds of scenarios?

frederikherema1

You are right, the REST-api only exposes a way to get the form-properties, not to submit them back (was added in 5.4 release).

There is an issue for this, http://jira.codehaus.org/browse/ACT-269, no concrete plans when this will be complete.